Our invention relates to a bearing for a shaft or shaft bearing located in a ball socket in a frame-mounted housing.
A shaft bearing for a shaft is known with a ball socket mounted in a substantially cylindrical cavity in a frame-mounted housing. The shaft is guided through the ball socket. The ball socket rests in a bearing seat in the housing formed at a base of the cavity and is pressed in the bearing seat by a structural member having a prestressed spring means providing a spring force, whereby the ball socket is movable in a radial direction against the spring force from the bearing seat.
These bearings are used in a positioning drive having a worm drive in which a ball socket receives the free end of a worm-gear shaft connected in one piece with the drive shaft of an electric drive motor. Especially, when the component to be moved, for example a sliding roof of a motor vehicle, is blocked, and the motor is still not switched off, the worm-gear shaft is bent elastically in the region of engagement to the worm gear. So that the shaft bearing is not jammed and/or broken, the free end of the worm-gear shaft guided in the ball socket can be adjusted to this bending. Therefore the ball socket must be rotatable and be liftable out from its bearing seat. After the bending back of the elastic worm-gear shaft the ball socket should be again returned to its initial position. The spring means provides for the required restoring force and should provide a certain ball socket-rotational moment reliably in all allowed rotational directions. The reason for the arrangement of the shaft in a ball socket is to provide a simple bearing operation and assembly of the drive, since the ball socket automatically compensates for alignment errors of the bearing passage or cavity.
A shaft bearing is described in German Open Patent Application DE-OS 23 51 062, in which the spring means are formed by a U-shape spring clip, whose U-legs are clamped at their free ends by an angle piece between the housing and the housing cover. The spring clip presses with its U-base engaged on the ball socket under compression on the ball socket, because the height of the U-shaped clip is less than the portion of the ball socket projecting above the angle piece. The spring clip rests thus only pointwise on the central portion of the ball socket, so that the ball socket rotational moment is not guaranteed to be equal in all directions.